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KINGDOM OF SAUDI ARABIA
GENERAL AUTHORITY OF CIVIL AVIATION
SAUDI AIR NAVIGATION SERVICES
AERONAUTICAL INFORMATION MANAGEMENT
P. O. BOX 929, JEDDAH - 21421
     
  AIC
Series A
AIC 07/2020
20 OCT 2020
 
     

  NOTICE ON ICAO AMENDMENTS TO WAKE TURBULENCE SEPARATION STANDARDS

  Purpose of the circular

This circular is to advise pilots and all stakeholders on ICAO adoption of new:

  1. aircraft category known as SUPER category applicable for the Airbus A380-800, or other future aircraft types exceeding the "HEAVY" wake turbulence categories;

  2. wake turbulence has been re-categorized into four "wake turbulence categories ". These categories are used to group aircraft based on the maximum certificated take-off mass, wingspan, and speeds known as "wake turbulence groups".

  3. update on Radiotelephony procedures for air-ground voice communication.

The adoption of the new aircraft category SUPER will induce the following changes:

  1. The use of the term SUPER category in radiotelephony between pilots operating such type and ATC during in flight or ground movements at airports; and

  2. insertion of code letter "J" in flight planning and ATS messages related to the flight operations of SUPER category.

These changes are applicable on 5 November 2020 and will be notified by NOTAM

  Background.

All aircraft, including helicopters, generate vortices as a consequence of producing lift. The heavier the aircraft and the more slowly it is flying, the stronger the vortex. Vortices are especially persistent in calm conditions. They are most hazardous to aircraft with a small wingspan during the take-off, initial climb, final approach and landing phases of flight.
Wake turbulence separation minima are the spacings between aircraft, determined either by time or distance, to be applied so that aircraft do not fly through the wake of a preceding aircraft within the area of maximum vortices.
Runway capacity during peak traffic is linked to the applicable separation minima on arrival or departure phases of flight, which is largely determined by wake turbulence.
In order to address runway capacity constraints, ICAO introduced a re-categorization of wake turbulence categories (RECAT) that may be authorized as an alternative to the existing ICAO wake separation standards. The new wake turbulence separation standards were adopted as amendment 9 to the fifteenth edition of the Procedures for Air Navigation Services - Air Traffic Management (PANS-ATM, ICAO Doc 4444), for applicability on 5 November 2020.
This amendment will provide the foundational of the Aviation System Block Upgrades (ASBU) WAKE thread and the framework for WAKE Block 2 and Block 3.
The introduction of a more efficient set of wake turbulence categorization builds on the operational experiences from the various implementation of wake turbulence separation schema such as those approved by the European Aviation Safety Agency (EASA) and the Federal Aviation Administration (FAA). It also enables the integration of the recommendations set in ICAO State letter TEC/OPS/SEP- 08-0294.SLG issued on 8 July 2008 regarding wake turbulence aspects of Airbus A380-800(A388) aircraft, with specific separation minima, specific phraseology (SUPER) and wake turbulence letter code (J).

  Wake turbulence categories and groups of aircraft

The new ICAO wake turbulence separations will be referred to as "Wake Turbulence Groups", while the wake turbulence separations currently in use will be referred to as "Wake Turbulence categories". The "Wake Turbulence categories" includes a new category SUPER(J) into the existing wake turbulence categories (HEAVY (H), MEDIUM (M), LIGHT (L)), to include A380-800 and other similar and future aircraft types and introduces alternative wake turbulence provisions that expand the four existing ICAO wake turbulence categories into seven wake turbulence groups that are defined using the maximum certificated take-off mass, wingspan, and speeds. The seven group designators are as follows:
Group Description
GROUP A - aircraft types of 136 000 kg or more, and a wingspan less than or equal to 80 m but greater than 74.68 m
GROUP B - aircraft types of 136 000 kg or more, and a wingspan less than or equal to 74.68 m but greater than 53.34 m;
GROUP C - aircraft types of 136 000 kg or more, and a wingspan less than or equal to 53.34 m but greater than 38.1 m
GROUP D - aircraft types less than 136 000 kg but more than 18 600 kg, and a wingspan greater than 32 m
GROUP E - aircraft types less than 136 000 kg but more than 18 600 kg, and a wingspan less than or equal to 32 m but greater than 27.43 m
GROUP F - aircraft types less than 136 000 kg but more than 18 600 kg, and a wingspan less than or equal to 27.43 m;
GROUP G - aircraft types of 18 600 kg or less (without wingspan criterion).
The seven groupings facilitate the use of optimized separation minima between specific traffic pairs which are frequently observed at capacity constrained airports leading to increased safety, efficiency and capacity.

  Special Wake turbulence Separation Standards

The ICAO wake turbulence groups described above, enables the separation between some aircraft pairs to be reduced, which will therefore increase capacity. In the current set of separation minima, the separation had been established taking into account the strongest wake generators and least resistant followers. The reduction in separation minima from the baseline current wake turbulence separation minima is justified by the fact that wake turbulence groups take into account that some aircraft generate weaker wake, or that some followers have a higher resistance factor to wake turbulence. The separation minima reduction results from the transposition of the equivalent proportional reduction in distance separation minima for the corresponding aircraft group pairs.
The Wake turbulence groups separation minima on departure and arrival may be progressively introduced at capacity constrained airports after the development of a validation study and a local safety case for each implementation. When implemented, the Wake turbulence groups separation minima must be based on measuring times between successive aircraft as follows:
Arriving aircraft: The following minima shall be applied to aircraft landing behind a SUPER, a HEAVY or a MEDIUM aircraft:
Following aircraft
Leading aircraft   Super Heavy Medium Light
Super No wake turbulence separation minima required 2 Minutes 3 Minutes 4 minutes
Heavy No wake turbulence separation minima required No wake turbulence separation minima required 2 Minutes 3 Minutes
Medium No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required 3 Minutes
Light No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required
Departing aircraft: When using wake turbulence categories, the following minimum separations shall be applied:
Following aircraftdeparting from the same RWY
Leading aircraft   Super Heavy Medium Light
Super No wake turbulence separation minima required 2 Minutes 3 Minutes 3 Minutes
Heavy No wake turbulence separation minima required No wake turbulence separation minima required 2 Minutes 2 Minutes
Medium No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required 2 Minutes
Light No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required
Departing aircraft: When using the seven wake turbulence groupings, the following minimum separations shall be applied:
Following aircraftdeparting from the same RWY
Leading aircraft Wake turbulence Group A B C D E F G
  Aircraft type samples A380-800 A124/A330/B777 MD11/B767 B757/A320/B737 E190/ DH8D E170/ CRJ1 CL30
A A380-800 No wake turbulence separation minima required 100s 120s 140s 160s 160s 180s
B A124/A330/B777 No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required 100s 120s 120s 140s
C MD11/B767 No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required 80s 100s 100s 120s
D B757/A320/B737 No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required 120s
E E190/ DH8D No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required 100s
F E170/ CRJ1 No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required
G Cessna 170 No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required No wake turbulence separation minima required
Where the separation minima required for IFR flights are greater than the recommended separation for wake turbulence, the IFR separation minima shall be applied.
When a flight is operating visually (i.e. IFR or SVFR operating under the reduced separation in the vicinity of aerodromes, VFR, or IFR making a visual approach) and is following or crossing behind another aircraft, the pilot is to be informed of the recommended wake turbulence separation minima.

  Implementation of wake turbulence groups.

The on-going revision of GACA regulation (GACARs) mainly Parts 91, 171 will not mandate the implementation of the new ICAO wake turbulence groups until the certificated service providers demonstrate full capability to comply with the requirements of the new ICAO wake turbulence groups.
However, GACAR Parts 91 and 171 will introduce new requirements on use of the SUPER category in radiotelephony between pilots and ATC, and code letter "J" in flight planning and ATS messages that are applicable on 5 November 2020.
The requirements on wake turbulence categories standards will be maintained as the application of the wake turbulence groups will only be applicable at capacity constrained airports or where improvement in operational efficiency is deemed necessary.
The implementation of wake turbulence groups separation minima is required at capacity constrained airports and must be subject of a validation and readiness study covering local safety case developed by Air Traffic Service Provider certificated under GACAR Part 171.
The implementation is expected to provide:

  1. benefits through increased runway throughput as well as reduced delays, especially during peak traffic periods and quicker recovery time from degraded operating conditions (e.g. low visibility procedures) to nominal operations; and

  2. a corresponding reduction in fuel use and CO2 emissions, which improves the environmental performance of aviation.

For any aircraft type of SUPER category, the term "SUPER" must be used in the initial radiotelephony contact between the aircraft and ATS units and the following phraseology must be used on and in the vicinity of the aerodrome.
TAXI PROCEDURES É for departure a) [aircraft type] [wake turbulence category if "super" or "heavy"] [aircraft location] REQUEST TAXI [intentions];
b) [aircraft type] [wake turbulence category if "super" or "heavy"] [aircraft location] (flight rules) TO (aerodrome of destination) REQUEST TAXI [intentions]
c) TAXI TO HOLDING POINT [number] [RUNWAY (number)] [HOLD SHORT OF RUNWAY (number) (or CROSS RUNWAY (number))] [TIME (time)];
É where detailed taxi instructions are required d) [aircraft type] [wake turbulence category if "super" or "heavy"] REQUEST DETAILED TAXI INSTRUCTIONS;
The new phraseology that must be used for SUPER category aircraft ground movements is applicable on 5 November 2020.
For the flight planning and exchange of ATS messages, the letter Code J must be used in item 9 of the ICAO flight plan and ATS messages for any SUPER category in accordance with ICAO Doc 4444, Appendix 2 and Appendix 3. This amendment is applicable on 5 November 2020.
The validation and readiness study required for the implementation of ICAO wake turbulence groups must at least cover the following:
Service provider Topics & action items
Air Traffic Services provider certified under GACAR Part 171

  1. adapt existing ATS systems e.g. local flight plan systems and air traffic controllers' HMI, adapt local procedures and develop local safety cases.

  2. Amend the Air Traffic Service Procedures Manual (ATSPM) Part 1

  3. deliver awareness training to ATCOs and operational Staff.

  4. implement post-implementation monitoring process to ensure continued safety reviews.
ATC schools certified under GACAR Part 144

  1. Review the training material.

  2. deliver awareness training to ATC instructors on the ICAO Doc 4444 amendment.
Aircraft operators certified under GACAR Parts 119, 121, 125, 133 and 135.

  1. Review and check the operational documentation, and

  2. Deliver awareness training to flight crews.

  Additional information

Further information and guidance on special wake turbulence separation standards can be obtained from:
CAPT. Saeed Gharmallah Alhumrani Abdullah Moham. Albathi

General Manager - Flight Operation Standards

General Authority of Civil Aviation

General Manager - Airspace Standards

General Authority of Civil Aviation
E-mail: salhumrani@gaca.gov.sa E-mail: abalbathi@gaca.gov.sa
Hatim Abdullah Murad

General Manager - Legislation

General Authority of Civil Aviation
E-mail: hmurad@gaca.gov.sa